David Howells wrote:
+ /* set up my own style of waitqueue */
+ waiter.task = tsk;
+
Any reason why you're setting up your own style of waitqueue in
mutex-simple.c instead of just using the kernel's style of waitqueue?
+
+/*
+ * release a single token back to a mutex
+ * - entered with lock held and interrupts disabled
+ * - the queue will not be empty
+ */
+void __up(struct mutex *mutex)
+{
+ struct mutex_waiter *waiter;
+ struct task_struct *tsk;
+
+ /* grant the token to the process at the front of the queue */
+ waiter = list_entry(mutex->wait_list.next, struct mutex_waiter, list);
+
+ /* we must be careful not to touch 'waiter' after we set ->task = NULL.
+ * - it is an allocated on the waiter's stack and may become invalid at
+ * any time after that point (due to a wakeup from another source).
+ */
+ list_del_init(&waiter->list);
+ tsk = waiter->task;
+#ifdef CONFIG_DEBUG_MUTEX_OWNER
+ mutex->__owner = tsk;
+#endif
+ mb();
This should be smp_mb(), I think.
+ waiter->task = NULL;
+ wake_up_process(tsk);
+ put_task_struct(tsk);
+}
Thanks,
Nick
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
